MRI

MRI

Magnetic Resonance Imaging ( MRI) is a medical appliance in diagnostic inspection area of radiology , yielding imaging of body organ with using magnetic field with power among 0,064 – 1,5 tesla ( 1 tesla = 1000 Gauss) and vibration resonance to hydrogen atom nucleus core 1. Some excess factors, especially the ability of making cutting of koronal, sagital, and aksial of oblik without many manipulations of patient body position, so that very aplicable to diagnostic of soft tissue. Technique depiction of MRI is relative complex because yielded picture depend on many parameters. If elections all the parameter precise, quality draw MRI can give detail of the image of human being body with contrast difference, so that body network pathology and anatomy can evaluate accurately.
To resulted the image of MRI with optimal quality to diagnostic, hence have to do the technique depiction of MRI, among other:
a. Preparation of patient and also good patient diagnostic technique
b. Contrast according to inspection;
Hereinafter when MRI evaluated from the type:
a. MRI owning open framework ( gantry open) with wide room and
b. MRI owning framework ( ordinary gantry) which is have narrow; tight alley
While evaluated from the strength of magnet
a. High MRI Tesla ( High Field Tesla ) having the power of above 1 – 1,5 T
b. MRI Tesla is ( Medium Field Tesla) having the power of 0,5 – T
c. low MRI Tesla ( Low Field Tesla) having the power of below/under 0,5 T.
Better a hospital choose MRI with high tesla because the appliance can be used to more fast Scan. So that we earn made many slices of body which vary briefest during. With many picture variation of image make diagnostic process become more specific
History
In the year 1946, Felix Bloch and of Purcell tell the theory, that atomic nucleus have the character of as small magnet, and atomic nucleus make spinning and processing. From invention then born appliance of Nuclear Magnetic Resonance (NMR) Spectrometer that it just use in chemistry. After more than ten years Raymond Damadian work by means of NMR Spectrometer, hence in the year 1971 he uses the appliance for the inspection of patient. In the year 1979, The University Nottingham Group of produce the image cutting of coronal and of sagittal ( beside cutting of aksial) with NMR. Hereinafter the AMERICAN COLLEGE of RADIO-LOGI ( 1984), NMR altered to become Magnetic Resonance Imaging ( MRI) and put down in Radiology shares.
The Principle work of MRI.
In outside moment magnetic body, Hydrogen atomic structure of human have random direction and do not balance. Later then moment put down in appliance of MRI (gantry), hence atom of H will parallel with magnet field direction. And so do vector spinning and processing will parallel with field direction of magnet. When given radio frequency, hence atom H will absorb of energy radio frequency. As a result the increased of energy, atom H will experience deflection, influenced by size and the duration radio energy frequency given. Radio time of frequency discontinued hence atom of H will parallel return with magnet field direction. At the time of return, atom of H will transmit energy. Then the signal energy detected by special detector. Hereinafter computer will process and reconstruct image obtained from various slice. Signal.
Marginally instrument of MRI consist of :

• Magnet system to make magnetic field. To be can operating MRI better, we shall have knowledge concerning about : magnet type, magnetic field effect, magnet of shielding ; coil shimming of plane of MRI
• Image system to make form image which consist of three coils bobbin, that is : 1.Gradien coil of X, to make cutting image of sagittal. 2 . Coil Gardien of Y, to make cutting image of coronal 3. Coil Z Gradien to make cutting image of aksial . When coil gradien of X, Y and Z work concurrently hence will be formed cutting of oblik
• Radio Frequensi System to make stimulant radio frequency and also detect signal
• Computer system to make awaken pulse sequins, controlling all appliance components of MRI and saving some images
• Print image system to print picture in film of rongent or for the saving of image
  The aim of Inspection of MRI is to know characteristic of morphologic ( location, measure, form, extension and other is differ from situation of patologis).

The target can be obtained by judging one or combination image body of aksial, sagittal, koronal or oblik depend on organ situation and possibility of his pathology. As for type inspection of MRI as according to organ to be seen, for example :

1. Inspection of head to see disparity : gland of pituitary, ear hole in , eye cavity , sine
2. Inspection of brain to detect : stroke / infark, image of brain function, haemorrahage, infection; tumor, disparity of wafting, disparity of vein like aneurisma, angioma, degeneracy process, atrofi
3. Inspection of backbone to see Degeneracy process ( HNP), tumor, infection, trauma, disparity of wafting
4. Inspection of Musculo- skeletal for the organ of : knee, shoulder , elbow, wrist, ankle , foot/feet , to detect cartilage robekan, tendon, ligament, tumor, infection / abscess etc. ;
5. Inspection of Abdomen to see liver , kidney, bile channel and sack;bag, pakreas, spleen, gynecological organ, prostate,
6. Inspection of Thorax to see : lounge, heart